Electric bell



(No Model.)

J. P. MOLAUGHLIN.

ELECTRIC BELL.

No. 393,998. Patented Dec. 4, 1888.

INVENTOR.

44% .z ttorney WITNESSES,

NiTEn STATES PATENT OEEicE.

JAMES F. MCLAI GHLIN, OF PHILADELPHIA, PENNSYLVANIA.

ELECTRIC BELL.

SPECIFICATION forming part of Letters Patent No. 393,998, dated December 4, 1888.

Application filed October 1, 1888.

To {LZZ whom it may concern:

Be it known that I, .lAMEs I. \ICLA'UGHLIN, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pen nsylvania, have in vented certain new and useful ln'iprovements in Electric Bells, of which the following is a specification.

My invention has reference to that kind of electric bells in which, when the circuit is closed at the transmitting end, an arn'iature actuated by an electro-magnet included in said circuit and located at the receiving end is made to intermittently interrupt and close said circuit, and the bell-hannner carried by the armature is caused to strike a bell anumber of remn'rent blows. Such bells are technically known as trembler-bells, and my improvements have the object of rendering such electric trcmbler-bell very sensitive, so that it; will respond to very faint currents, and that the strolws upon the bell will recur with greater rapidity than was heretofore deemed practicable. some of my improvements are, however, also applicable to single-stroke bells.

I use in my improved bell a magnet having a single energizing-coil only, whereby the manufacture of the same cheapened and simplified, all of which will more fully appear from the following detailed description, in which referei'ice is madetotheaccompanying drawings, in which I have shown, in

Figure l, a top plan view of my electric bell with the bell or gong itself removed, and in Fig. an inverted plan view with a portion of the sustaining-frame cut away to more completely disclose the operative parts.

Like numerals of reference indicate like parts in both figures of the drawings.

1 use by preference an annular frame, I, of metal, provided on dian'ietrically opposite sides with projecting lugs 2 2, by which the frame is secured in place by screws or otherwise.

A bracke 3 l, projecting inwardly from and in one piece with the frame, has the core of the electro-magnet i secured to it by a screw, 5, and the same screw also secures the angular pole-extension 0, one arm of which is interposed between the core of the magnet and the vertical arm 3 of the bracket. The other arm, which is at right angles to the first,

Serial No. 286,921. (No model.)

extends parallel with the axis of the magnet a short distance beyond the middle thereof. From the vertical arm 23 of bracket 3 3 extends a radial arm, 7, overthe electro-magnet t0 the center of the annular frame, and is there provided with a boss, 8, to which the bell 9 is screwed or otherwise attached. Another bracket, it), also projecting inwardly from the annular frame and in one piece with the latter, has a spring, ll, secured to it, and said spring supports the angular armature 1;, one arm of which, 13, extends over the end of the core of the elect ro-magnet, while the other arm, it, extends parallel with aml on one side of the electro-magnet to a short distance beyond the middle thereof, occupyin a position between the electro-magnet and the extended pole-piece t3 and m'erlapping the latter. It will now be seen that the active poles of the electro-magnet -1- are the free end of the core of said electro-magnet and the free end of the polar extension 6, and that when the electromagnet is energized the arm 13 of the armature will be attracted by the free end of the core, and the arm .14 of said armature will be attracted by the polar extension (3. The two forces act in the same sense upon the armature, and both will tend to bend the spring 11 in the same direction. tonsequently, while the electro-magnet 4 is provided with a single coil. only, both poles of the same will act in unison to attract the arimiture, and they will both act with substantially the same force, since their distances from the respective arms of the armature are equal, and. since the portions of said arms which constitute the centers of attraction for the respective poles of the magnet are at equal distances from the point; of support of spring 11. The two arms of the armature therefore give the sameleverage. This diagrammatically indicated by a dotted curved line, 15, which represents a portion of a circle drawn from the point 1b as a center. From the point 17, where spring 11 and armature 12 are connected, said spring extends slightly curved over the arm 13 of the armature, and is at its free end 18 provided with a platinum contact, and the platinum-tipped screw it), working in an insulated post, 20, is adjusted to make contact with the platinum-faced extension of spring 11.

One bindingpost, ill, mounted upon a lug,

22, extending from the annular frame, receives one of the circuit-wires, 23, while the other circuit-wire, 24:, is clamped into a bindingpost, 25, mounted upon and insulated from another lug, 26. The insulated binding-post is connected by a wire, 27, with one terminal of'the coil of the electro-magnet, and the insulated post is connected by a wire, 28, with the other terminal of said coil. The incoming current passes "from circuit-wire to binding-post 21, and through the frame 1 to spring 11, and by the platinum-faced free end of said spring to contact-screw 19', and from the insulated supporting-post 20 of the same, by wire 28, to and through the coil of electromagnet 4, which it leaves by wire 27, and then passes by insulated binding-post and wire 24 either to ground or to the returnvire. By the passage of the current through the coilof the electro-magnet the latter is energized and the armature 12 is attracted in the manner hereinbefore described, whereby the circuit is broken at the contacts 18- 19, and is again established by the reaction of spring 11, when by the breaking of the cireuit the magnet becomes de-energi'zed, and this operation is repeated so long as the circuit is closed at the transmitting-station. The armature is thus rapidly vibrated, and the signal is produced by the bell-hammer 29, secured to the armature by the slightly-elastic arm 30. This arm is so curved as to bring the hammer normally between the inner wall of the bell 9 and a sounding-stud, 9, extending inwardly from and cast in one piece with the same and quite close to both of them. The bell-hammer is thus made to strike alternately the body of the bell and the stud its excursions being limited to within the corner between the two. Thus for each make and break of the circuit at 18 19 the bell will be sounded twice, and this by a very limited sweep of the bell-hammer.

Having now fully described my invention, I claim and desire to secure by Letters Patent 1. In an electric bell, the combination of an electro ma gnet having a single energizingco'il and a core with one of the poles extended, with a two-armed angular armature, one arm of which extends into operative relation to one pole and the other arm into like operative relation to the other pole of the electromagnet, substantially as described.

2. In an electric bell, the combination of an electro-magnet having a single energizingcoil and a core having one rectangular polar extension, with a vibratory rectangular armature, one arm of which is in operative relation to the free end of the core and the other arm in like operative relation to the polar extension, substantially as described. 7 r

3. In an electric bell, the combination of an electro-magnet having a single energizingcoil and a core having one free end and a rectangular polar extension secured to the other end, with a vibratory rectangular arma ture, one arm of which extends within attractive distance of the free end of the core and the other arm within the same attractive distance of the polar extension, with the centers of attraction of the two arms at the same distance from the axis of operation, substantially as described.

4. In an electric trembler-belhthe combination of an electro-magnet and a circuitbreaking armature for the same, with a bell having an interior sounding-stud cast in one piece with the same, and a bell-hammer carried by the armature within the corner formed by'the body of the bell and the soundingstud andwithin striking distance of both, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

I JAMES F. MCLAUGHLIN. WVitnesses:

JULiUs HIRSHFELD, FRANK IWL MILL-ER. 

